In 3GPP (3rd Generation Partnership Project) which is a project aiming to standardize a mobile communication system, specifications of a home base station, which is a small base station provided in a home or a company, are discussed (see Non Patent Document 1).
A home base station forms a specific cell such as a CSG (Closed Subscriber Group) cell or a hybrid cell. The CSG cell is a cell accessible only by a user terminal (called a “CSG member”) having an access permission. The hybrid cell is accessible by other terminals other than the CSG member, but the CSG member is advantageously treated.
In addition, it is noted that a “cell” is used as a term indicating a minimum unit of a radio communication area, and is also used as a term indicating a function of performing radio communication with a user terminal.
In a handover procedure of a user terminal to a specific cell, a mobility management device included in a core network performs verification (access control) of the user terminal for access permission to the specific cell.